Glenn Beck revealed on Monday evening that there’s a medical reason he came across so “crazy” during his time at Fox News.

In a tearful address on TheBlaze, Beck said that for the past five years, he’s been battling a rare neurological illness that caused him nearly intolerable pain and that, until only recently, no doctors were able to diagnose.

While at Fox (where he was until 2011), Beck was plagued by pain so severe that “my hands or feet or arms and legs would feel like someone had crushed them or set them on fire or pushed broken glass into my feet.” It was so bad, he says, that his camera crew would have hand signals for when to take the camera off of him. On top of that, he was only getting two to four hours of sleep a night—doctors said he hadn’t had a real REM sleep in close to a decade—but he never once felt tired. “I could have been lifting cars during my time at Fox,” he said of his nearly 24-hour work schedule.

The first sign of trouble was what he called a “time collapse,” meaning he couldn’t remember at what point events in his life happened. Then, he could no longer remember names, faces or entire conversations. All the while, he was still suffering pain, macular dystrophy, vision loss, vocal cord paralysis, and frequent seizures.

“We went to doctor after doctor. We even looked into someone poisoning me,” he said. “Each doctor had a new finding and they left me with more questions and no answers… It has baffled some of the best doctors in the world it has frightened me and my family.”

It was then that he decided it was best to leave New York City and relocate to Texas, where he now has a massive studio in Irving for TheBlaze. Then, 18 months ago, he took a test for tramautic brain injury. He tested in the bottom 10 percent and was told he would have five to 10 years before he would no longer be able to function at all.

It was only this summer that doctors at a brain research center told him he “several things going” including an autoimmune disorder and the beginning of an adrenal shutdown, which is what caused his superstrength during his time at Fox. For the past 10 months, with treatment including “electric stimulation,” he’s been able to reverse the adrenal shutdown, saying the last time he took his TBI test, he was at 90 percent capacity.